August 2006 arXiv papers — page 6

Yi Ming Zou

The problem of computing the index of a coincidence isometry of the hyper cubic lattice $\mathbb{Z}^{n}$ is considered. The normal form of a rational orthogonal matrix is analyzed in detail, and explicit formulas for the index of certain coincidence isometries of $\mathbb{Z}^{n}$ are obtained. These formulas generalize the known results for $n\le 4$.

Yi Ming Zou

The structure of the coincidence symmetry group of an arbitrary $n$-dimensional lattice in the $n$-dimensional Euclidean space is considered by describing a set of generators. Particular attention is given to the coincidence isometry subgroup (the subgroup formed by those coincidence symmetries which are elements of the orthogonal group). Conditions under wh

R. Jimenez, Yu. V. Muranov, D. Repovš

The paper introduces a group $LSP$ of obstructions for splitting a homotopy equivalence along a pair of submanifolds. We develop exact sequences relating the $LSP$-groups with various surgery obstruction groups for manifold triple and structure sets arising from triples of manifolds. The natural map from the surgery obstruction group of the ambient manifold

R. Jimenez, Yu. V. Muranov, D. Repovš

Cappell and Shaneson pointed out in 1978 interesting properties of Browder - Livesay invariants which are similar to differentials in some spectral sequence. Such spectral sequence was constructed in 1991 by Hambleton and Kharshiladze. This spectral sequence is closely related to a problem of realization of elements of Wall groups by normal maps of closed ma

M. Cencelj, Yu. V. Muranov, D. Repovš

The problem of splitting a homotopy equivalence along a submanifold is closely related to the surgery exact sequence and to the problem of surgery of manifold pairs. In classical surgery theory there exist two approaches to surgery in the category of manifolds with boundaries. In the $ rel \partial$ case the surgery on a manifold pair is considered with the

I. Assem, T. Brüstle, R. Schiffler, G. Todorov

Let A be a hereditary algebra over an algebraically closed field. We prove that an exact fundamental domain for the m-cluster category of A is the m-left part of the m-replicated algebra $A^{(m)}$ of A. Moreover, we obtain a one-to-one correspondence between the tilting objects in the m-cluster category (that is, the m-clusters) and those tilting $A^{(m)}$-m

S. V. Ludkovsky

The article is devoted to approximate, global and along curves differentiability of functions over non-archimedean infinite fields with non-trivial valuations. Fields with zero and non-zero characteristics are considered. Spaces of differentiable functions are defined with the help of partial difference quotients. Approximate differentiability is studied rel

J. Scott Carter, Abhijit Champanerkar

An elementary, albeit higher dimensional, argument is used to compute the area under the power function curve between 0 and 1.

Jiro Adachi, Go-o Ishikawa

Motivated by the importance and universal character of phase singularities which are clarified recently, we study the local structure of equi-phase loci near the dislocation locus of complex valued planar and spatial waves, from the viewpoint of singularity theory of differentiable mappings, initiated by H. Whitney and R. Thom. The classification of phase-si

Yongxia Hua, Radu Saghin, Zhihong Xia

We consider partially hyperbolic diffeomorphisms on compact manifolds where the unstable and stable foliations stably carry some unique non-trivial homologies. We prove the following two results: if the center foliation is one dimensional, then the topological entropy is locally a constant; and if the center foliation is two dimensional, then the topological

L. Pastur

We study the variance and the Laplace transform of the probability law of linear eigenvalue statistics of unitary invariant Matrix Models of n-dimentional Hermitian matrices as n tends to infinity. Assuming that the test function of statistics is smooth enough and using the asymptotic formulas by Deift et al for orthogonal polynomials with varying weights, w

H. Hedenmalm, S. Shimorin, A. Sola

The reproducing kernel function of a weighted Bergman space over domains in ${\mathbb C}^d$ is known explicitly in only a small number of instances. Here, we introduce a process of orthogonal norm expansion along a subvariety of codimension 1, which also leads to a series expansion of the reproducing kernel in terms of reproducing kernels defined on the subv

Yehuda Pinchover, Gershon Wolansky, Daphne Zelig

We study the discreteness of the spectrum of Schrodinger operators which are defined on N-dimensional rooted trees of a finite or infinite volume, and are subject to a certain mixed boundary condition. We present a method to estimate their eigenvalues using operators on a one-dimensional tree. These operators are called width-weighted operators, since their

Ivan Kausz

In this note we give a definition of stable maps into the classifying stack $\BGL_r$ of the general linear group. To support our belief that the definition is the correct one, we show that there are natural boundary morphisms between the moduli groupoids parameterizing stable maps to $\BGL_r$.

Gabriela Jeronimo, Guillermo Matera, Pablo Solerno, Ariel Waissbein

We exhibit a probabilistic symbolic algorithm for solving zero-dimensional sparse systems. Our algorithm combines a symbolic homotopy procedure, based on a flat deformation of a certain morphism of affine varieties, with the polyhedral deformation of Huber and Sturmfels. The complexity of our algorithm is quadratic in the size of the combinatorial structure

Gilles Blanchard, François Fleuret

We establish a generic theoretical tool to construct probabilistic bounds for algorithms where the output is a subset of objects from an initial pool of candidates (or more generally, a probability distribution on said pool). This general device, dubbed "Occam's hammer'', acts as a meta layer when a probabilistic bound is already known on the

Alexander Zimmermann

Let $A$ be a symmetric $k$-algebra over a perfect field $k$. Külshammer defined for any integer $n$ a mapping $ζ\_n$ on the degree 0 Hochschild cohomology and a mapping $κ\_n$ on the degree 0 Hochschild homology of $A$ as adjoint mappings of the respective $p$-power mappings with respect to the symmetrizing bilinear form. In an earlier paper it is shown that

Apostolos Beligiannis, Henning Krause

An Artin algebra is by definition virtually Gorenstein if the class of modules which are right orthogonal (with respect to Ext^*(-,-)) to all Gorenstein projective modules coincides with the class of modules which are left orthogonal to all Gorenstein injective modules. We provide a new characterization in terms of finitely generated modules. In addition, an

Shinya Sakuma

In this paper, we study the subalgebra generated by two Ising vectors in the Griess algebra of a vertex operator algebra. We show that the structure of it is uniquely determined by some inner products of Ising vectors. We prove that the order of the product of two $τ$-involutions is less than or equal to 6 and we determine the inner product of two Ising vect

M. Brozos-Vazquez, P. Gilkey

We study the geometry of pseudo-Riemannian manifolds which are Jacobi--Tsankov, i.e. J(x)J(y)=J(y)J(x) for all tangent vectors x and y. We also study manifolds which are 2-step Jacobi nilpotent, i.e. J(x)J(y)=0 for all tangent vectors x and y.

Jin Hong Kim

The aim of this paper is to show the rigidity of homologically trivial actions of prime order on K3 surfaces. To be precise, we show that homotopy K3 surfaces do not admit a periodic diffeomorphism of odd prime order 3 acting trivially on cohomology. Moreover, we give an obstruction in terms of the rationality and sign of the spin numbers to the existence of

Ayan Mahalanobis

In this paper we find a necessary and sufficient condition for a finite nilpotent group to have an abelian central automorphism group.

Alice Chang, Jie Qing, Paul Yang

In this paper we develop a bubble tree structure for a degenerating class of Riemannian metrics satisfying some global conformal bounds on compact manifolds of dimension 4. Applying the bubble tree structure, we establish a gap theorem, a finiteness theorem for diffeomorphism type for this class, and a diameter bound for a family of conformal metricssatisfyi

Takuro Mochizuki

We establish the correspondence between tame harmonic bundles and $μ_L$-stable parabolic Higgs bundles with trivial characteristic numbers. We also show the Bogomolov-Gieseker type inequality for $μ_L$-stable parabolic Higgs bundles. Then we show that any local system on a smooth quasi projective variety can be deformed to a variation of polarized Hodge stru

Brooke Shipley

We show that the homotopy theory of differential graded algebras coincides with the homotopy theory of HZ-algebra spectra. Namely, we construct Quillen equivalences between the Quillen model categories of (unbounded) differential graded algebras and HZ-algebra spectra. We also construct Quillen equivalences between the differential graded modules and module

Thomas Thiemann

This is a (relatively) non -- technical summary of the status of the quantum dynamics in Loop Quantum Gravity (LQG). We explain in detail the historical evolution of the subject and why the results obtained so far are non -- trivial. The present text can be viewed in part as a response to an article by Nicolai, Peeters and Zamaklar [hep-th/0501114]. We also

Ofer Aharony, Alex Buchel, Amos Yarom

We study the short distance (large momentum) properties of correlation functions of cascading gauge theories by performing a tree-level computation in their dual gravitational background. We prove that these theories are holographically renormalizable; the correlators have only analytic ultraviolet divergences, which may be removed by appropriate local count

Atsushi Nakamula

A q-deformation of the ADHMN caloron construction is considered, under which the anti-selfdual (ASD) conditions of the gauge fields are preserved. It is shown that the q-dependent Nahm data with certain constraints are crucial to determine the ASD gauge fields, as in the case of ordinary caloron construction. As an application of the q-deformed ADHMN constru

Pedro F. Gonzalez-Diaz

It is proposed that the current acceleration of the universe is not originated by the existence of a mysterious dark energy fluid nor by the action of extra terms in the gravity Lagrangian, but just from the sub-quantum potential associated with the CMB particles. The resulting cosmic scenario corresponds to a benigner phantom model which is free from the ma

Spencer Chang, Patrick J. Fox, Neal Weiner

The presence of a new singlet scalar particle a can open up new decay channels for the Higgs boson, through cascades of the form h -> 2a -> X, possibly making discovery through standard model channels impossible. If a is CP-odd, its decay products are particularly sensitive to physics beyond the standard model. Quantum effects from heavy fields can naturally

V. Ravindran, J. Smith, W. L. van Neerven

We present threshold enhanced QCD corrections to rapidity distributions of di-leptons in the Drell-Yan process and of Higgs particles in both gluon fusion and bottom quark annihilation processes using Sudakov resummed cross sections. We have used renormalisation group invariance and the mass factorisation theorem that these hard scattering cross sections sat

A. Vogt, S. Moch, J. Vermaseren

We summarize recent higher-order QCD results based, directly or indirectly, on the Mellin-space computation of the next-to-next-to-leading-order splitting functions governing the evolution of hadronic parton distributions. Specifically, we briefly present third-order results for the coefficient functions in inclusive deep-inelastic scattering (including the

I. P. Lokhtin, A. M. Snigirev

The method to simulate the rescattering and energy loss of hard partons in heavy ion collisions has been developed. The model is a fast Monte-Carlo tool introduced to modify a standard PYTHIA jet event. The full heavy ion event is obtained as a superposition of a soft hydro-type state and hard multi-jets. The model is applied to analysis of the jet quenching

A. Szczurek, R. S. Pasechnik, O. V. Teryaev

We discuss double-diffractive (double-elastic) production of the $η'$-meson in the $pp \to pη'p$ reaction within the formalism of unintegrated gluon distribution functions (UGDF). We estimate also the contribution of $γ^* γ^* \to η'$ fusion. The distributions in the Feynman $x_F$ (or rapidity), transferred four-momenta squared between initial and

R. V. Gavai, Sourendu Gupta

In this talk I present the logic behind, and examine the reliability of, estimates of the critical end point (CEP) of QCD using the Taylor expansion method.

A. Abulencia et al.

We report an upper limit on the fraction of V+A current, $f_{V+A}$, in top quark decays, using approximately 700 pb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay $t \to Wb \to \ell νb$ (where $\ell=e$ or $μ$), the invariant mass of the charged lepton and the bottom quark jet is se

Marco Selvi

The Large Volume Detector (LVD) in the INFN Gran Sasso National Laboratory, Italy, is a $ν$ observatory mainly designed to study low energy neutrinos from the gravitational collapse of galactic objects. The experiment has been monitoring the Galaxy since June 1992, under increasing larger configurations: in January 2001 it has reached its final active mass M

V. A. Bednyakov, J. A. Budagov, A. V. Gladyshev, D. I. Kazakov

Prospects for ATLAS observation of a SUSY-like signal from two gluinos are investigated within a certain region of the mSUGRA parameter space, where the cross section of the two gluinos production via gluon-gluon fusion is estimated at a rather high level of 13 pb. The event selection trigger uses a very clear signature of the process (4 jets + 4 muons + up

James M. Overduin, Hans S. Plendl

Leopold Halpern, who was a close associate of both Erwin Schroedinger and Paul Dirac before making his own mark as a theoretical physicist of the first rank, died in Tallahassee, Florida on 3 June 2006 after a valiant struggle with cancer. We give an outline of his life and work, including his progress towards a unified gauge theory of gravitation and spin.

Yi Pan

As currently designed, the signal-recycling cavity (SRC) in the Advanced-LIGO interferometer is degenerate. In such a degenerate cavity, the phase fronts of optical fields become badly distorted when the mirror shapes are slightly deformed due to mirror figure error and/or thermal aberration, and this causes significant loss of the signal power and the signa

Lorenzo Iorio

In this paper we test the hypothesis that the Pioneer anomaly can be of gravitational origin by comparing the predicted model-independent shifts Delta a/a for the semimajor axis of Uranus and Neptune with the Voyager 2 radio-technical distance measurements performed at JPL-NASA. As in the case of other tests based on different methods and data sets (secular

Stephane Fay, Morad Amarzguioui

In this paper, we confront the predictions of the power law cardassian model for the baryon power spectrum with the observations of the SDSS galaxy survey. We show that they fit only for very unusual values of the cold dark matter or baryon density parameters, the Hubble parameter or the spectral index of the initial power spectrum. Moreover, the best-fit Ca

Luis A. Lopez, Nora Breton

We present the study of exact inhomogeneous cosmological solutions to a four-dimensional low energy limit of string theory containing non-minimal interacting electromagnetic, dilaton and axion fields. We analyze Einstein-Rosen solutions of Einstein-Maxwell-dilaton-axion equations and show, by explicitly taken the asymptotic limits, that they have asymptotica

Zhao Ren, Li Huai-Fan, Zhang Sheng-Li

Recently, Hawking radiation of the black hole has been studied by using the tunnel effect method. It is found that the radiation spectrum of the black hole is not a strictly pure thermal spectrum. How does the departure from pure thermal spectrum affect the entropy? This is a very interesting problem. In this paper, we calculate the partition function throug

Zhao Ren, Zhang Sheng-Li

Recently, Hawking radiation of the black hole has been studied using the tunnel effect method. It is found that the radiation spectrum of the black hole is not a strictly pure thermal spectrum. How does the departure from pure thermal spectrum affect the entropy? This is a very interesting problem. In this paper, we calculate the partition function by energy

B. Hudzia, M-T. Kechadi, A. Ottewill

In this paper we proposed a hierarchical P2P network based on a dynamic partitioning on a 1-D space. This hierarchy is created and maintained dynamically and provides a gridmiddleware (like DGET) a P2P basic functionality for resource discovery and load-balancing.This network architecture is called TreeP (Tree based P2P network architecture) and is based on

Chih-Chun Wang

Code annealing, a new method of designing good codes of short block length, is proposed, which is then concatenated with cyclic lifting to create finite codes of low frame error rate (FER) error floors without performance outliers. The stopping set analysis is performed on the cyclically lifted code ensemble assuming uniformly random lifting sequences, and t

T. N. Ellahi, B. Hudzia, L. McDermott, T. Kechadi

Grid computing has enabled pooling a very large number of heterogeneous resource administered by different security domains. Applications are dynamically deployed on the resources available at the time. Dynamic nature of the resources and applications requirements makes needs the grid middleware to support the ability of migrating a running application to a

Leonid B. Litinskii, Dmitry E. Romanov

We present an algorithm of clustering of many-dimensional objects, where only the distances between objects are used. Centers of classes are found with the aid of neuron-like procedure with lateral inhibition. The result of clustering does not depend on starting conditions. Our algorithm makes it possible to give an idea about classes that really exist in th

Benoit Hudzia, Serge Petiton

Grid environments have recently been developed with low stretch and overheads that increase with the logarithm of the number of nodes in the system. Getting and sending data to/from a large numbers of nodes is gaining importance due to an increasing number of independent data providers and the heterogeneity of the network/Grid. One of the key challenges is t

B. Hudzia, T. N. Ellahi, L. McDermott, T. Kechadi

During the last decade there has been a huge interest in Grid technologies, and numerous Grid projects have been initiated with various visions of the Grid. While all these visions have the same goal of resource sharing, they differ in the functionality that a Grid supports, characterization, programming environments, etc. We present a new Grid system dedica

B. Hudzia, L. McDermott, T. N. Illahi, M-T. Kechadi

During the last decade there has been a huge interest in Grid technologies, and numerous Grid projects have been initiated with various visions of the Grid. While all these visions have the same goal of resource sharing, they differ in the functionality that a Grid supports, the grid characterisation, programming environments, etc. In this paper we present a

Robert Colvin, Ian J. Hayes, Paul Strooper

The refinement calculus for logic programs is a framework for deriving logic programs from specifications. It is based on a wide-spectrum language that can express both specifications and code, and a refinement relation that models the notion of correct implementation. In this paper we extend and generalise earlier work on contextual refinement. Contextual r

Michael Hohensee

In this paper, we examine the cause of the border effect observed in many mobility models used to construct simulations of ad hoc networking protocol performance. We specify conditions under which a node mobility model must produce spatial mobile node distribution functions that obey the diffusion equation. In particular demonstrate that these conditions are

Nicolas Brodu

This is an algorithm for finding neighbors when the objects can freely move and have no predefined position. The query consists in finding neighbors for a center location and a given radius. Space is discretized in cubic cells. This algorithm introduces a direct spherical indexing that gives the list of all cells making up the query sphere, for any radius an

Rene Fluekiger, Paola Lezza, Marco Cesaretti, Carmine Senatore

The simultaneous addition of various Carbon based additives (in the present case B4C + SiC) to Mg and B powders has been introduced as a new concept in view of enhancing the superconducting parameters Bc2, Birr and Jc values of in situ Fe/MgB2 wires. A series of Fe sheathed monofilamentary wires of 1.1 mm diameter with a MgB2 core of 600 microm diameter was

Paul H. Barsic, Oriol T. Valls, Klaus Halterman

We study the thermodynamics of clean, layered superconductor/ferromagnet nanostructures using fully self consistent methods to solve the microscopic Bogoliubov-deGennes equations. From these self-consistent solutions the condensation free energies are obtained. The trilayer SFS junction is studied in particular detail: first order transitions between 0 and $

M. Chauvin, P. Vom Stein, H. Pothier, P. Joyez

We have measured the effect of microwave irradiation on the dc current-voltage characteristics of superconducting atomic contacts. The interaction of the external field with the ac supercurrents leads to replicas of the supercurrent peak, the well known Shapiro resonances. The observation of supplementary fractional resonances for contacts containing highly

A. Barhdadi, S. Karbal, N. Mgafad, A. Benmakhlouf

Mercury-Sensitized Photo-Assisted Chemical Vapor Deposition (Hg-Photo-CVD) technique opens new possibilities for reducing thin film growth temperature and producing novel semiconductor materials suitable for the future generation of high efficiency thin film solar cells onto low cost flexible plastic substrates. This paper provides some experimental data res

E. H. Hwang, S. Das Sarma

We theoretically study transport properties of a two-dimensional electron system on a hydrogen-passivated Si(111) surface in the field-effect-transistor (FET) configuration. We calculate the density and temperature dependent mobility and resistivity for the recently fabricated Si(111)-vacuum FET by using a semiclassical Boltzmann theory including screened ch

A. Barhdadi

Mercury-Sensitized Photo-Assisted Chemical Vapor Deposition (Hg-Photo-CVD) technique opens new possibilities for reducing thin film growth temperature and producing novel semiconductor materials suitable for the future generation of high efficiency thin film solar cells onto low cost flexible plastic substrates. This paper provides an overview of this techni

Rumi De, G. Ananthakrishna

We investigate the peel front dynamics and acoustic emission of an adhesive tape within the context of a recent model by including an additional dissipative energy that mimics bursts of acoustic signals. We find that the nature of the peeling front can vary from smooth to stuck-peeled configuration depending on the values of dissipation coefficient, inertia

Oleh Baran, Deniz Ertas, Gary S. Grest, Thomas C. Halsey

We report numerical results for velocity correlations in dense, gravity-driven granular flow down an inclined plane. For the grains on the surface layer, our results are consistent with experimental measurements reported by Pouliquen. We show that the correlation structure within planes parallel to the surface persists in the bulk. The two-point velocity cor

Eric Roman, Jonathan R. Yates, Marek Veithen, David Vanderbilt

We compute from first principles the infrared dispersion of the nonlinear susceptibility $\chi^{(2)}$ in zincblende semiconductors. At terahertz frequencies the nonlinear susceptibility depends not only on the purely electronic response $\chi^{(2)}_{\infty}$, but also on three other parameters $C_1$, $C_2$ and $C_3$ describing the contributions from ionic mo

Sascha Zöllner, Hans-Dieter Meyer, Peter Schmelcher

We study the correlation properties of the ground states of few ultracold bosons, trapped in double wells of varying barrier height in one dimension. Extending previous results on the signature of the transition from a Bose-condensed state via fragmentation to the hard-core limit, we provide a deeper understanding of that transition by relating it to the los

A. Yu. Galkin, B. A. Ivanov, C. E. Zaspel

The dispersion relations for collective magnon modes for square-planar arrays of vortex-state magnetic dots, having closure magnetic flux are calculated. The array dots have no direct contact between each other, and the sole source of their interaction is the magnetic dipolar interaction. The magnon formalism using Bose operators along with translational sym

Shin-ichi Kimura, Takafumi Mizuno, Hojun Im, Katsuyuki Hayashi

Temperature-dependent infrared reflectivity spectra of SrFe$_{4}$Sb$_{12}$ has been measured. A renormalized Drude peak with a heavy effective mass and a pronounced pseudogap of 10 meV develops in the optical conductivity spectra at low temperatures. As the temperature decreases below 100 K, the effective mass ($m^{*}$) rapidly increases, and the scattering

S. Kimura, J. Sichelschmidt, J. Ferstl, C. Krellner

We report far-infrared optical properties of YbRh$_{2}$Si$_{2}$ for photon energies down to 2 meV and temperatures 0.4 -- 300 K. In the coherent heavy quasiparticle state, a linear dependence of the low-energy scattering rate on both temperature and photon energy was found. We relate this distinct dynamical behavior different from that of Fermi liquid materi

R. Valenti, T. Saha-Dasgupta, H. O. Jeschke, B. Rahaman

We present a comparative study of the coupled-tetrahedra quantum spin systems Cu2Te2O5X2, X=Cl, Br (Cu-2252(X)) and the newly synthesized Cu4Te5O12Cl4 (Cu-45124(Cl)) based on ab initio Density Functional Theory calculations. The magnetic behavior of Cu-45124(Cl) with a phase transition to an ordered state at a lower critical temperature T$_c$=13.6K than in C

L. Isella, J. Ruostekoski

We study the splitting of a harmonically trapped atomic Bose-Einstein condensate when we continuously turn up an optical lattice (or a double-well) potential. As the lattice height is increased, quantum fluctuations of atoms are enhanced. The resulting nonequilibrium dynamics of the fragmentation process of the condensate, the loss of the phase coherence of

S. I. Dorozhkin, J. H. Smet, K. von Klitzing, L. N. Pfeiffer

The magnetoresistance oscillations, which occur in a two-dimensional electron system exposed to strong microwave radiation when the microwave frequency $ω$ coincides with the n-th subharmonic of the cyclotron frequency $ω_c$ have been investigated for n = 2, 3 and 4. It is shown that these subharmonic features can be explained within a non-equilibrium energy

N. T. Bagraev, N. G. Galkin, W. Gehlhoff, L. E. Klyachkin

We present the first findings of the spin transistor effect in the Rashba gate-controlled ring embedded in the p-type self-assembled silicon quantum well that is prepared on the n-type Si (100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the value of the external magnetic field and the top gate

N. T. Bagraev, M. I. Bovt, O. N. Guimbitskaya, L. E. Klyachkin

The CV measurements and tunneling spectroscopy are used to study the ballistic transport of the spin-polarized holes by varying the value of the Rashba spin-orbit interaction (SOI) in the p-type quantum well prepared on the surface of the n-CdF2<Y> bulk crystal. The findings of the hole conductance oscillations in the plane of the p-type quantum well that ar

N. T. Bagraev, W. Gehlhoff, L. E. Klyachkin, A. M. Malyarenko

We present the findings of high efficient light absorption in self-assembled quantum wells (SQW) embedded in silicon microcavities that exhibit a distributed feedback identified by the FIR transmission spectra. The excitonic normal-mode coupling (NMC) is found to result in high efficient bound exciton photoluminescence in the range of the Rabi splitting. The

I. A. Shelykh, N. T. Bagraev, N. G. Galkin, L. E. Klyachkin

We analyse the conductance of the Aharonov - Bohm (AB) one- dimensional quantum ring touching a quantum wire. The period of the AB oscillations is shown to be dependent strongly on the chemical potential and the Rashba coupling parameter that is in a good agreement with the studies of such a device prepared on the Si(100) surface.

N. T. Bagraev, M. I. Bovt, W. Gehlhoff, O. N. Guimbitskaya

We present the findings of the spin-dependent transport of the 2D holes in the p-type ultra-narrow self-assembled silicon quantum well (Si-QW) confined by the superconductor barriers on the n-type Si (100) surface. The Aharonov-Casher conductance oscillations caused by the Rashba spin-orbit interaction are found to interplay with the quantization phenomena i

Andres Santos

The model of inelastic Maxwell particles (IMP) allows one to derive some exact results which show the strong influence of inelasticity on the nonequilibrium properties of a granular gas. The aim of this work is to propose a simple model kinetic equation that preserves the most relevant properties of the Boltzmann equation (BE) for IMP and reduces to the BGK

O. Patsahan, A. Ciach

Correlation functions in the restricted primitive model are calculated within a field-theoretic approach in the one-loop self-consistent Hartree approximation. The correlation functions exhibit damped oscillatory behavior as found before in the Gaussian approximation [Ciach at. al., J. Chem. Phys. {\bf 118}, 3702 (2003)]. The fluctuation contribution leads t

I. V. Solovyev

Using an effective low-energy Hamiltonian derived from the first-principles electronic structure calculations for the narrow $t_{2g}$ bands of YTiO$_3$, LaTiO$_3$, YVO$_3$, and LaVO$_3$, we evaluate the contributions of the correlation energy ($E_C$) to the stability of different magnetic structures, which can be realized in these distorted perovskite oxides

M. T. Batchelor, X. -W. Guan

We discuss recent results on the relation between the strongly interacting one-dimensional Bose gas and a gas of ideal particles obeying nonmutual generalized exclusion statistics (GES). The thermodynamic properties considered include the statistical profiles, the specific heat and local pair correlations. In the strong coupling limit $γ\to \infty$, the Tonk

S. Galambosi, M. Knaapila, J. A. Soininen, K. Nygård

We present a non-resonant inelastic x-ray scattering study at the carbon K-edge on aligned poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl] and show that the x-ray Raman scattering technique can be used as a practical alternative to x-ray absorption measurements. We demonstrate that this novel method can be applied to studies on aligned $π$-conjugated polymers

M. Schechter, P. C. E. Stamp, N. Laflorencie

The spin-glass phase in the $\LHx$ compound is considered. At zero transverse field this system is well described by the classical Ising model. At finite transverse field deviations from the transverse field quantum Ising model are significant, and one must take properly into account the hyperfine interactions, the off-diagonal terms in the dipolar interacti

HyungJoon Cho, Paola Cappellaro, David G. Cory, Chandrasekhar Ramanathan

We have measured the decay of NMR multiple quantum coherence intensities both under the internal dipolar Hamiltonian as well as when this interaction is effectively averaged to zero, in the cubic calcium fluoride (CaF2) spin system and the pseudo one-dimensional system of fluoroapatite. In calcium fluoride the decay rates depend both on the number of correla

M. T. Clark, M. R. Paul

We consider the stochastic dynamics of an array of two closely spaced atomic force microscope cantilevers in a viscous fluid for use as a possible biomolecule sensor. The cantilevers are not driven externally, as is common in applications of atomic force microscopy, and we explore the stochastic cantilever dynamics due to the constant buffeting of fluid part

Michelle D. Chabot, John M. Moreland, Lan Gao, Sy-Hwang Liou

We report on the design, fabrication, and implementation of ultrasensitive micromechanical oscillators. Our ultrathin single-crystal silicon cantilevers with integrated magnetic structures are the first of their kind: They are fabricated using a novel high-yield process in which magnetic film patterning and deposition are combined with cantilever fabrication

D. I. Golosov, D. Orgad

We calculate the energy of a boundary between ferro- and antiferromagnetic regions in a phase separated double-exchange magnet in two and three dimensions. The orientation dependence of this energy can significantly affect the geometry of the phase-separated state in two dimensions, changing the droplet shape and possibly stabilizing a striped arrangement wi

S. Ashhab, J. R. Johansson, Franco Nori

We study the decoherence dynamics of a qubit coupled to a quantum two-level system (TLS) in addition to its weak coupling to a background environment. We analyze the different regimes of behaviour that arise as the values of the different parameters are varied. We classify those regimes as two weak-coupling regimes, which differ by the relation between the q

Matthias Vojta, Thomas Vojta, Ribhu K. Kaul

Using a phenomenological lattice model of coupled spin and charge modes, we determine the spin susceptibility in the presence of fluctuating stripe charge order. We assume the charge fluctuations to be slow compared to those of the spins, and combine Monte Carlo simulations for the charge order parameter with exact diagonalization of the spin sector. Our cal

P. v. Doetinchem, S. Fopp, W. Karpinski, T. Kirn

For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. The TRD has 20 layers of fleece radiator with Xe/CO2 proportional mode straw tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb.

Matthew W. Muterspaugh, Benjamin F. Lane, S. R. Kulkarni, B. F. Burke

The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) has monitored 37 sub-arcsecond binary systems to determine whether their Keplerian orbits are perturbed by faint astrometric companions to either star. Software has been developed to evaluate the regions in a companion mass-period phase space in which the PHASES observations can exc

Arti Garg, Christopher W. Stubbs, Peter Challis, W. Michael Wood-Vasey

We present a set of 11 type Ia supernova (SN Ia) lightcurves with dense, pre-maximum sampling. These supernovae (SNe), in galaxies behind the Large Magellanic Cloud (LMC), were discovered by the SuperMACHO survey. The SNe span a redshift range of z = 0.11 - 0.35. Our lightcurves contain some of the earliest pre-maximum observations of SNe Ia to date. We also

S. G. Djorgovski, C. Donalek, A. Mahabal, R. Williams

We review some of the recent developments and challenges posed by the data analysis in modern digital sky surveys, which are representative of the information-rich astronomy in the context of Virtual Observatory. Illustrative examples include the problems of an automated star-galaxy classification in complex and heterogeneous panoramic imaging data sets, and

Leonid Chuzhoy

We derive the density profile of cold dark matter halos using a self-similar accretion model. We show that if the clumpiness of the infalling matter is taken into account, then the inner density slope, d(log{rho})/d(log{r}), is close to -1. Compared with the density profiles predicted by different numerical simulations, we find that outside ~0.1% of the viri

J. S. Alcaniz

The high-quality cosmological data, which became available in the last decade, have thrusted upon us a rather preposterous composition for the universe which poses one of the greatest challenges theoretical physics has ever faced: the so-called dark energy. By focusing our attention on specific examples of dark energy scenarios, we discuss three different ca

Z. Balog, G. H. Rieke, K. Y. L. Su, J. Muzerolle

We present 24 micron images of three protoplanetary disks being photoevaporated around high mass O type stars. These objects have ``cometary&#39;&#39; structure where the dust pulled away from the disk by the photoevaporating flow is forced away from the O star by photon pressure on the dust and heating and ionization of the gas. Models of the 24 micron and

E. Momjian, J. D. Romney, C. L. Carilli, T. H. Troland

We present phase-referenced VLBI results on the radio continuum and the OH 18 cm megamaser emission from the Ultra-Luminous Infrared Galaxy, IRAS 17208--0014. The observations were carried out at 1599 MHz using the Very Long Baseline Array, the phased VLA, and the Green Bank Telescope. The highest resolution radio continuum results show several compact sourc

Elmar Koerding, Sebastian Jester, Rob Fender

Hardness-intensity diagrams (HIDs) have been used with great success to study the accretion states and their connection to radio jets in X-ray binaries (XRBs). The analogy between XRBs and active galactic nuclei (AGN) suggests that similar diagrams may help to understand and identify accretion states in AGN and their connection to radio loudness. We construc

C. M. Raiteri, M. Villata, M. Kadler, M. A. Ibrahimov

A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided informatio

Giuseppe Bertin, Antonio Cava

Context. We consider a simple self-gravitating disk, made of two fluid components characterized by different effective thermal speeds and interacting with one another only through gravity; two-component models of this type have often been considered in order to estimate the impact of the cold interstellar medium on gravitational instabilities in star-dominat

C. van Breukelen, L. Clewley, D. G. Bonfield, S. Rawlings

We present the first cluster catalogue extracted from the UKIRT Infrared Deep Sky Survey Early Data Release. The catalogue is created using UKIDSS Ultra Deep Survey infrared J and K data combined with 3.6 micro-m and 4.5 micro-m Spitzer bands and optical BVRi&#39;z&#39; imaging from the Subaru Telescope over 0.5 square degrees in the Subaru XMM-Newton Deep F